Wheelchair lift apparati for use in vehicles are known. For example, Braun et al U.S. Pat. No. 4,664,584 discloses a rotary wheelchair lift including a hydraulic lift having a vertically telescoping slide tube and a horizontal wheelchair platform attached to the lower end thereof. A platform extension accommodates wheelchairs of various sizes and types. An in/out switch causes the platform to be rotated into and out of the vehicle. A fold-down handrail permits the user to safely ride with the apparatus into the vehicle, and then wheel off the platform to the vehicle controls as the driver. For dismounting from the vehicle, the user reverses the procedure by first rolling onto the platform.
Koerber U.S. Pat. No. 4,493,602 discloses another rotary wheelchair lift apparatus for automatically lifting the user from ground level into the van and then out of the van without any need for the user to leave the wheelchair. The apparatus includes a vertical drive screw driven by a motor via a pulley belt, in conjunction with a one-way clutch. A further pivotally mounted motor and drive screw serve to pivot the support column and lift frame.
Wolfe U.S. Pat. No. 5,052,879 discloses a wheelchair lift and transfer system designed to enable a user to independently enter a vehicle and drive the vehicle from his or her wheelchair without leaving the wheelchair platform. It includes the platform and an associated fold-down ramp, with vertical lift cylinders connected to the side of the platform adjacent the vehicle, and horizontal cylinders connected to the vertical cylinders to pull the platform along tracks into the vehicle.
Williams et al U.S. Pat. No. 4,493,603 discloses still another wheelchair lift apparatus for positioning a wheelchair under the steering wheel. This apparatus includes a drive motor and vertical screw for lifting and lowering, and a motor and gear reduction unit, pinion, and gear sector for pivoting.
Quercy U.S. Pat. No. 4,551,060 discloses a motor and vertical screw driven platform which is then pivotable along a rail to a position beneath a fold-down vehicle seat.
Dake U.S. Pat. No. 4,096,955 discloses a lifting mechanism including cantilevered arms vertically and pivotally movable for moving a wheelchair and its occupant to and from a van, and further including tilting means for tilting the wheelchair and occupant prior to lifting for the occupant's safety during lifting.
Gates U.S. Pat. No. 4,133,437 discloses a wheelchair lift apparatus including a rotatable post, a pivotally mounted motor for rotating the post through a pinion and gear drive, and a carriage slidable along the post via a motor driven belt and pulley for driving a lead screw.
Boone U.S. Pat. No. 5,106,121 discloses a bench seat structure which is adapted to be removably coupled to the vehicle floor pan and which may be readily replaced by the inventive wheelchair lift apparatus.